Evaluation of the immunogenicity of human iPS cell-derived neural stem/progenitor cells in vitro

Abstract

To achieve the goal of a first-in-human trial for human induced pluripotent stem cell (hiPSC)-based transplantation for the treatment of various diseases, allogeneic human leukocyte antigen (HLA)-matched hiPSC cell banks represent a realistic tool from the perspective of quality control and cost performance. Furthermore, considering the limited therapeutic time-window for acute injuries, including neurotraumatic injuries, an iPS cell bank is of potential interest. However, due to the relatively immunoprivileged environment of the central nervous system, it is unclear whether HLA matching is required in hiPSC-derived neural stem/progenitor cell (hiPSC-NS/PC) transplantation for the treatment of neurodegenerative diseases and neurotraumatic injuries. In this study, we evaluated the significance of HLA matching in hiPSC-NS/PC transplantation by performing modified mixed lymphocyte reaction (MLR) assays with hiPSC-NS/PCs. Compared to fetus-derived NS/PCs, the expression levels of human leukocyte antigen-antigen D related (HLA-DR) and co-stimulatory molecules on hiPSC-NS/PCs were significantly low, even with the addition of tumor necrosis factor-α (TNFα) and/or interferon-γ (IFNγ) to mimic the inflammatory environment surrounding transplanted hiPSC-NS/PCs in injured tissues. Interestingly, both the allogeneic HLA-matched and the HLA-mismatched responses were similarly low in the modified MLR assay. Furthermore, the autologous response was also similar to the allogeneic response. hiPSC-NS/PCs suppressed the proliferative responses of allogeneic HLA-mismatched peripheral blood mononuclear cells (PBMCs) in a dose-dependent manner. Thus, the low antigen-presenting function and immunosuppressive effects of hiPSC-NS/PCs result in a depressed immune response, even in an allogeneic HLA-mismatched setting. It is crucial to verify whether these in vitro results are reproducible in a clinical setting.

Capacity of Retinal Ganglion Cells Derived from Human Induced Pluripotent Stem Cells to Suppress T-Cells

“…When HLA class I of transplanted cells is recognized by immune cells, CD8-positive cytotoxic T-cells are activated to eliminate the grafts [22][23][24]. HLA class II, CD80, and CD86 co-stimulatory molecules are expressed on the antigen-presenting cells [25,31,38]. Our findings imply that iPSC-RGCs are less likely to activate CD8-positive cytotoxic T-cells and do not have an antigen-presenting function.…”

“…We next performed the MLR assay to examine whether iPSC-RGCs inhibit activated immune cells. The MLR assay is widely used to evaluate allogeneic immune responses in vitro [28][29][30][31][32]. We used iPSCs as a control (TLHD2 line).…”

“…In the present study, we evaluated the immunogenicity of iPSC-RGCs such as expression of HLA molecules, and CD80, CD86, and CD274 co-stimulatory molecules. We also investigated whether iPSC-RGCs have a T-cell suppression capacity using the mixed lymphocyte reaction (MLR) assay, which is extensively used for assessing immune rejection in vitro [28][29][30][31][32]. To elucidate the immunosuppressive property and the immunogenicity of human iPSC-derived RGCs (iPSC-RGCs) against lymphocytes, we used an in vitro model with iPSC-RGCs derived from healthy donors co-cultured with active lymphocytes isolated from the peripheral blood of healthy subjects.…”

Cell Transplantation for Spinal Cord Injury: Tumorigenicity of Induced Pluripotent Stem Cell-Derived Neural Stem/Progenitor Cells

“…Two reports revealed that despite the ability to differentiate into neural cells [ 19 , 22 ], iPSC-derived NS/PCs did not show any substantial improvement in function. Besides, it takes a long time to generate and evaluate iPSCs [ 23 ], making it unrealistic for individualized iPSC-based therapy because the optimal time for stem cell transplantation is the subacute phase [ 24 ]. As a result, either iPSCs would have to be generated from donor tissue, missing out on the major factor that makes them attractive in the first place, or transplanted at more chronic phases of injury [ 25 ], which showed a poor result after transplantation into the chronic SCI model.…”

Chemical compound-based direct reprogramming for future clinical applications

“…Currently, the characterization of pluripotency, differentiation potential, and genomic integrity in heterogeneous colonies of iPS cells is time-consuming and expensive, so it is not feasible that somatic cells isolated from each patient can be reprogrammed into iPS cells for their own transplantation therapy to avoid immune rejection [ 6 ]. Recently it has been reported that allogenic iPS cells with the same homozygous human leukocyte antigen (HLA) haplotype as the patient still can cause immune rejection responses in in vitro assay system [ 7 ]. The evidence also implies the importance of the use of each set of patient-derived autologous cells for their own transplantation therapy.…”